Means for cutting



Jan. 10, 1961 G. G. BROWN 2,967,381

MEANS FOR CUTTING Filed April 7. 1958 ll /W l k 26 I 24 l6 FIG. I ELECTRICAL GENERATOR FIG. 2

INVENTOR.

GILBERT 6. BROWN ATTORNEY ay-w United States Patent MEANS FOR CUTTING Gilbert G. Brown, Davenport, Iowa, assignor to The Bendix Corporation, a corporation of Delaware Filed Apr. 7, 1958, Ser. No. 726,961

1 Claim. (Cl. 51-157) This invention relates to methods and means for cutting frangible bodies and one of its objects is to provide improved methods and means for cutting such bodies.

While not limited thereto the invention relates particularly to slicing frangible bodies such, for example, as the ceramics and crystals used in the manufacture of transducers and electronic diodes and transistors; and an object of the invention is to provide an improved means for cutting and especially slicing frangible bodies.

Such materials have been sliced in the past with the aid of ultrasonics applied to a slicing tool and a slurry, comprising liquid and an abrasive, applied between the tool and the material being sliced. The tools comprise a series of thin, deep, parallel blades and these are usually specially shaped to aid in getting slurry to the leading edge of the tool. However, I have discovered that the cutting action in such an arrangement is greatly enhanced if instead of the tool, the material being cut is ultrasonically activated. Moreover, when the material being cut, rather than the tool, is activated, the tool can be much less complicated and can be arranged so that getting slurry to the leading edge of the tool is accomplished more efiiciently. The provision of this improved cutting method and the provision of such improved tools is another object of the invention.

A further object is to provide a method and a tool for slicing frangible substances in which the lateral vibration of former tools, resulting from the transmission of ultrasound waves, is materially reduced whereby thinner slices having sides more nearly parallel may be produced.

Another object is to provide a slicing method and tool in which the ultrasonic energy need not be transmitttd through the tool.

Other objects and advantages of the invention appear ing hereinafter will be apparent to those familiar in the art.

In the drawing:

Fig. 1 is a schematic illustration, partly in section and partly fragmented, of a form of apparatus for practicing the invention including a tool embodying the invention; and

Fig. 2 is a view in bottom elevation of the tool shown in Fig. 1.

The apparatus selected for illustration is advantageously used in practicing the specific example of the invention in which its use is hereinafter described, it being understood that both the method and apparatus may be modified and that other forms of the method and other embodiments of the invention are possible without departing from the spirit of the invention or the scope of the appended claim.

Referring to the drawing, means are provided for vibrating the frangible material to be cut at an ultrasonic frequency. A frangible material such as the ceramic body illustrated, is secured by convenient means such as "ice by cementing, as shown, to a transducer assembly. While any of the well known types of sonic transducers may be employed, the transducer assembly advantageously comprises a magnetostrictive core 12 whose windings 14 are supplied with energizing current of ultrasonic frequency by an electrical generator 16 connected in circuit with said windings. The transducer core is joined at its upper end by suitable means, to the wave transmitting element 18 to which the ceramic body 10 is secured.

The element 18 has upwardly extending side walls 20 forming a container for a slurry which drains therefrom through drain passages 21. A downwardly projecting wall 22 of element 18 extends through an opening in a supporting structure 24. The latter limits movement of element to substantially a vertical direction. A resilient gasket 26 is interposed between the wave transmitting element 18 and the support 24 whereby element 18 is supported but is permitted to move in the vertical direction substantially unhindered.

The cutting tool is disposed above the body 10 and the tool and transducer assembly are arranged for relative movement toward one another so that the tool may be moved into the ceramic body as shown. The tool advantageously comprises a series of wires circular in cross section, such as the piano wires 28 illustrated, tautly secured in parallel across the arms of a C-shaped holder 30. The wires may be secured by any convenient means such as by welding as shown at 32.

Holder 30 is fixed to a movable arm 34 in which is formed a passage 36. A slurry comprising a mixture of liquid and abrasive, advantageously water and alumina, or norbide particles, is introduced into passage 36 from whence it flows through an opening 38 in holder 30. Emerging from opening 38 the slurry flows into the slots being cut in the ceramic body 10 and around wires 38. For the sake of clarity the slurry is not shown; but disposed between the leading surface of the wires 28 and the ceramic body, it is activated by the ultrasound transmitted through the crystal so that cavitation is produced and the abrasive particles are made to vibrate.

As it is used herein, the word ultrasonic refers to mechanical wave action and does not refer to a wave action limited to any frequency or frequency range within or without the range of audible frequencies.

I claim:

In combination, a sonic wave transmitting holder for a ceramic element to be sliced, means for imparting sonic energy to said holder for transmission of vibratory motion to said ceramic element in a direction substantially perpendicular to said holder, a tool holder positioned above said wave transmitting holder and including a plurality of wires circular in cross-section and held taut in parallel spaced relation in a plane perpendicular to the line of vibratory motion imparted by said wave transmit- I ting holder, said tool holder being movable to carry said plurality of wires in the direction of said line of action, and means for flowing a slurry downwardly over I said wires in the direction of said wave transmitting holder.

References Cited in the file of this patent UNITED STATES PATENTS 2,580,716 Balamuth Jan. 1, 1952 2,774,194 Thatcher Dec. 18, 1956 2,796,702 Bodine June 25, 1957 2,813,377 Duran Nov. 19, 1957 2,83l,476 Wilson et al. Apr. 22, 1958 2,886,026 Stewart May 12, 1959 Patented Jan. 10, 1961 

